Piezoelectric / dielectric ceramics, piezoelectric elements, and sound generators

Alkaline earth metal-enriched core-shell structured alkali niobate ceramics address insulation and reliability issues in piezoelectric elements by enhancing electrical resistance and simplifying manufacturing, ensuring consistent performance and reduced defects.

JP7868969B2Active Publication Date: 2026-06-02TAIYO YUDEN KK
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Patent Information

Authority / Receiving Office
JP · JP
Patent Type
Patents
Current Assignee / Owner
TAIYO YUDEN KK
Filing Date
2021-12-17
Publication Date
2026-06-02

AI Technical Summary

Technical Problem

Existing piezoelectric elements face challenges in maintaining insulation and reliability due to silver diffusion during firing, leading to decreased electrical resistance and increased defect rates, especially in miniaturized multilayer piezoelectric elements, and manufacturing methods for lead-free ceramics are complex and difficult to control for mass production.

Method used

The use of alkali niobate-based piezoelectric ceramics with a higher concentration of alkaline earth metal elements near the surface, forming a core-shell structure, which enhances insulation resistance and suppresses silver diffusion, allowing for reliable piezoelectric elements and ceramic capacitors to be manufactured through a simpler process.

Benefits of technology

This approach results in highly reliable piezoelectric elements and ceramic capacitors with improved insulation resistance and reduced manufacturing complexity, utilizing a core-shell structure that stabilizes the distribution of components for consistent performance.

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Abstract

To provide an alkali niobium acid-based piezoelectric / dielectric ceramics which enables a highly reliable piezoelectric element and / or a highly reliable ceramics capacitor to be obtained and which can be produced by a simple method, and to provide a piezoelectric element, and a sounding body.SOLUTION: A piezoelectric / dielectric ceramics is constituted of a crystal particle 41 containing; a sodium alkali niobium having perovskite-type structure as a main component; and at least one alkali earth metal selected from calcium and barium. In at least one of the crystal particle 41, a ratio of a total mol number of calcium and barium to a mol number of contained niobium is higher than a center portion at a position where a distance from a front surface to a direction of the center portion is 5% of a diameter of the particle.SELECTED DRAWING: Figure 1
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